<div>
  <div>
    <input type="number" data-bind="value:count" />
    <input
      type="button"
      data-bind="click:handleChangeNumberCount"
      value="更改数量"
    />
  </div>
  <div>count: <span data-bind="text:count"></span></div>
  <div data-bind="foreach:{data:nums,as:'n'}">
    <div data-bind="text:n"></div>
  </div>
</div>
